Today, one of the Mason interns was troubled and confused as to why he couldn't achieve a below parallel squat without his pelvis slipping into posterior tilt, and lumbar spine into flexion . I describe this squatting mistake as "hyena butt." Come on, you've seen a hyena run…Their butt is always tucked in toward their front haunches…Or maybe it looks more like a scared dog tucking its tail…Whatever you want to call it, it’s not good. Here’s what’s happening or not happening when you see it, and some techniques to help remedy the situation.
Weak psoai are the primary culprit of hyena butt. Because few actively achieve hip flexion above 90 degrees (psoai aren’t activated below 90 degrees) during their weekly routines, the psoai become dormant. In situations requiring a significant amount of hip flexion, such as a below parallel squat, weak psoai will limit one’s ability to maintain proper pelvic anterior tilt, causing one to draw ROM from the lumbar spine. This compensation leads to the hyena butt.

Being able to maintain proper lumbar spine alignment during hip flexion is significant for a couple reasons. First, without proper lumbar spine alignment, hamstring and glute function will be compensated significantly limiting the generation and transmission of force. Second, lazy posai will often cause the other flexors of the hip to become tight and overactive. Frequent knee and back pain can be experienced with imbalances in this area. Lastly, the shear stress imposed on the spine during lumbar flexion is tremendous. Slap a couple hundred pounds on your back, as you would during a below parallel squat, then round that lower back (hyena butt), and by god you’ve mixed yourself a delicious cocktail called disc herniation…best if enjoyed supine.

But, there is still hope for all my hyena butt friends. There are a variety of drills to strengthen the psoai. They require quite a bit of precision, careful progression and typically the watchful eye of coach. Here's one taken from our online database of exercises used to coach our distance clients. It's called the "seated psoas march." Coaching cues include, sitting with the knees just above 90 degrees; point toes-up; lift foot off of ground while maintaining a neutral spine (lower back shouldn't move!).